Water movement in a plant sample by neutron beam analysis as well as positron emission tracer imaging system

We present water imaging of a plant sample both by neutron beam and positron emission tracer imaging system (PETIS). The former method provided static water profile in a plant sample as well as that in the vicinity of a root imbedded in soil. Not only X-ray film but also CT method using a cooled CCD camera is presented. Through non-destructive water image in an X-ray film, root development as well as 2-dimensional water movement toward the root was analyzed. Spatial water image was constructed from 180 CT projection images, taken at an interval of one degree while rotating the sample, through a CCD camera. In the case of a soybean root, there was a water gradient toward a root in soil and gave minimum value at about 1 mm far from the surface of a root. The water absorbing part in a root was gradually shifted downward with the root development. We also present real time water movement by PETIS, where water was labeled with a positron emitting nuclide, O-15. The transportation of O-15-water within a plant was relatively slow and water uptake was observed only at the lowest internode, between a root and the first leaf, during 20-minute measurement.